This study designed to determine prevalence and related factors of depression in student of Arak, Iran. An analytical cross-sectional study was conducted on 304 undergraduate medical and basic students in Arak Universities, Markazi Province, Iran from May 2008 to July 2008. GHQ-28 questionnaire has been used for data gathering and analyzed by t and Chi square tests. Mean of mental health in students was 26.18 +/- 11.02 and 52.3% of students scored above the threshold of the GHQ- 28, indicating psychiatric disorder. Female sex, uninteresting of major, an uncertain future and positive family history were the most important risk factors of depression. In results didn't observe any significant relationship between age, education major and year. The prevalence of depression was higher than as compared to all population and in female exceed to male students. But there wasn't any difference between medical and non medical students. So attention to financial and occupational future graduated and under graduated students is essential.